Fabry disease, affecting nearly 8,000 to 10,000 people worldwide, is a lysosomal storage disorder caused by inherited genetic mutations in the GLA gene, which results in deficient activity of the enzyme alpha-galactosidase A (alpha-Gal A). This deficiency leads to lysosomal accumulation of globotriaosylceramide, or GL-3, interferes with the body's ability to break down a specific fatty substance. Lifespan of male Fabry patients is reduced by 20 years, while that of females shrink by 15 years, with symptoms including pain, kidney failure and increased risk of heart attack and stroke.

Replagal, or agalsidase alfa, is "the only" human-cell-line-derived form of enzyme alpha-galactosidase A manufactured in a human cell line by gene activation. It is indicated for the long-term treatment of patients with a confirmed diagnosis of Fabry disease. Replagal is available to U.S. patients since December 2009 under an FDA-approved treatment protocol filed at the request of FDA.

Fast Track designation is an FDA-approved process that facilitates the development and expedites the review of drugs that treat serious diseases and fill an unmet medical need. It allows a company to file the sections of Biologics License Application, or BLA, as they become available instead of filing all the sections at once.

In December, the FDA had requested additional information for Shire's Replagal BLA. The FDA asked for additional human pharmacokinetic data to confirm comparability between product that manufactured in roller bottles and that manufactured in bioreactors. Product made by the bioreactor process is already approved for commercial use in the European Union as well as a number of other countries.

Shire noted that it withdrew the December BLA filing, and at the suggestion of the FDA, requested and received Fast Track designation. Shire also said that it would immediately initiate the rolling submission of the Replagal BLA, and submit the requested pharmacokinetic data around mid-year.

"We will continue to work closely with the FDA in the coming months on the rolling BLA submission for REPLAGAL. We remain committed to continuing to provide Fabry patients in the United States with REPLAGAL under the treatment protocol," said Sylvie Gregoire, President, Shire Human Genetic Therapies.

Earlier this month, Amicus Therapeutics (FOLD) reported additional positive preliminary data from ongoing Phase 2 extension study of its investigational drug Amigal, or migalastat Hcl, for Fabry disease. Amigal has orphan drug status in both the U.S and EU granted by the FDA and the EMEA.

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